Class Uttk::Strategies::HostSelector
In: lib/uttk/strategies/HostSelector.rb
Parent: Strategy

Example: 

  root: !S::Suite
    contents:
      - selector: !S::HostSelector
          hosts:                         # The list of hosts.
            - ssh://joe:tux@foo.com      # Via ssh on foo.com.
            - druby://bar.fr:4242/ttk    # Another custom protocol.
            - ...                        # Hosts can also be specified
                                         # with a file containing hosts
                                         # or an url.
          static_select: |               # Performed just one time.
            reject! { |x| not x.alive? } # Example of static cleaning.
            shuffle!                     # Shuffle the hosts.
          dynamic_select: |              # Called to elect an host.
            roll                         # Move the first host to the
                                         # end of the list and return it
                                         # Other examples:
                                         #   - first (take the first)
                                         #   - choose (randomly)
      - big suite: !S::Pool
          attribute: !S::Jump
            to: !url <<host_selector.elect>>
            test: !S::Suite
              ... something long ...
          contents:
            - ...
            - ...

Methods

assertion   call   do_dynamic_min   do_dynamic_select   do_static_select   elect_host   epilogue   prologue   run_impl  

Included Modules

Concrete

Public Instance methods

elect_host()

Methods

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 45
      def elect_host
        do_dynamic_select
      end

Protected Instance methods

assertion()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 111
      def assertion
        pass
        # ...
        super
      end
call( selector, argument )

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 49
      def call ( selector, argument )
        if selector.arity == 1
          selector[argument]
        else
          argument.instance_eval(&selector)
        end
      end
do_dynamic_min()

Suppose that we have URI::Generic#load_average which returns the current load average of the targeted host.

With dynamic select you can simply do that

dynamic_select: 

  min { |x, y| x.load_average <=> y.load_average }

dynamic_min: 

  load_average

dynamic_min: 

  ((alive?)? 0 : Float::MAX) + 3 * load_average.first + 5 * current_jobs_count

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 84
      def do_dynamic_min
        @hosts_pool.min { |x, y| call(dynamic_min, x) <=> call(dynamic_min, y) }
      end
do_dynamic_select()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 65
      def do_dynamic_select
        call(@dynamic_select, @hosts_pool)
      end
do_static_select()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 58
      def do_static_select
        @hosts_pool = @hosts.dup
        result = call(@static_select, @hosts_pool)
        @hosts_pool = result unless result.nil?
      end
epilogue()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 118
      def epilogue
        # ...
        super
      end
prologue()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 89
      def prologue
        super
        @static_select = @static_select.to_proc
        @dynamic_select = @dynamic_select.to_proc if @dynamic_select
        @dynamic_min = @dynamic_min.to_proc if @dynamic_min
        unless @dynamic_select or @dynamic_min
          raise ArgumentError, "Need at least dynamic_select or dynamic_min"
        end
        @symtbl[:host_selector] = self
        @symtbl['host_selector.elect''host_selector.elect'] = SymTbl::Trigger.new { elect }
        # ...
      end
run_impl()

[Source]

# File lib/uttk/strategies/HostSelector.rb, line 103
      def run_impl
        do_static_select
        # ...
        super
        # ...
      end

[Validate]